1. Field of the Invention
The present invention relates to the management of a communications system or network, and more particularly to the monitoring of xe2x80x9cstressxe2x80x9d in a network.
2. Description of the Related Art
The following description is concerned with a data communications system such as a local area network (LAN), that is an Ethernet network. However, the skilled person will appreciate that the present invention will have more general applicability to other types of managed networks including wireless networks.
A local area network (LAN) typically comprises a plurality of computers, computer systems, workstations and other electronic devices connected together by a common media such as twisted pair or coaxial cable or fibre optic cable. Data can be communicated between devices on the network by means of data packets (or frames) in accordance a predefined protocol.
Computers and other devices connected to a network can be managed or unmanaged devices. A managed device has processing capability which enables it inter alia to monitor data traffic sent from, received at, and passing through the ports of the device. Monitored data associated with the ports of the network device is stored in memory on the network device. Unmanaged devices do not have this processing capability.
It is becoming increasingly common and necessary for an individual to be appointed to manage a network. The appointed network manager (or administrator) utilises a network management station which includes network management hardware and software. In particular, the network management station is able to access management data from managed network devices using an appropriate management protocol (e.g. the SNMP protocol) and display this data for use by the network manager.
Known network management systems simply read the management data from the managed network devices and present this data to the network manager, typically in the form of numeric text, substantially unchanged. The network manager is expected to interpret the data in managing the network.
One of the important tasks of a network manager is to assess the operational performance of the various network devices and links as well as the network as a whole. The network manager needs to know when problems are arising within the network and which particular network devices are responsible for such problems etc.
Typical problems which may affect the performance of a network include:
1. slow operating speed of the network, and individual network devices, leading to slow movement of data traffic across the network, indicated by e.g. slow response time for a given network device;
2. high volumes of data traffic on the network due to e.g. over-utilisation of the network links, network devices and the network as a whole; and
3. high error rates in the transmission of data packets across the network, indicated by e.g. the loss of data packets in a network device and errors in received data packets.
The aforementioned problems which occur in the operation of a network contribute to the poor xe2x80x9chealthxe2x80x9d of a network. The concept of the health of a network is well known in the field of network management. In the present description, however, it is more convenient to refer to the xe2x80x9cstressxe2x80x9d of a network (or network device or link) rather than its xe2x80x9chealthxe2x80x9d. It will be understood that a high level of stress equates to a low level of health and vice versa. Although the present invention is described as monitoring stress in a network, it will be appreciated that the present invention is equally applicable to monitoring health in a network.
Problems which affect the performance of a network, and therefore contribute to the level of xe2x80x9cstressxe2x80x9d, may be of greater or lesser significance. For instance, a problem with the operating speed of an end station may be less significant than a problem with the operating speed of a central core device such as a switch. Thus, the level of stress of a network depends upon a number of factors including device type, network media type and the type of problem occurring. The network manager must take all such factors into account when interpreting the management data received from the managed network devices to establish whether the performance of the network is satisfactory.
It would be desirable for a network management system to monitor characteristics of network devices and links which are indicative of problems occurring in a network which contribute to xe2x80x9cstressxe2x80x9d, (such characteristics are referred to herein as xe2x80x9cmetricsxe2x80x9d) and provide data to the network manager indicative of the level of stress which is easy to interpret. It would further be desirable to determine a value indicating the overall performance of each network object (a xe2x80x9cnetwork objectxe2x80x9d is defined herein as a network device or link) on a network and/or the overall performance of parts of, or all of, the network, so that the network manager would not be required to interpret the monitored data, but could immediately ascertain the performance of the network (or part of the network) from the value provided by the network management system.
In accordance with a first aspect, the present invention provides a method for processing data representing monitored characteristics in a network comprising network devices and links to provide a stress value representing the performance of the network or a part thereof, the method comprising:
obtaining a raw value of data for a monitored characteristic of a network device or link;
comparing said raw value with a predetermined threshold value for said monitored characteristic;
if said raw data value is greater than or equal to said threshold value, providing a stress value equal to a default value, said default value being a maximum or minimum value of a predefined bounded range; and
if said raw value is less than said threshold value, calculating a stress value within said predefined bounded range using an appropriate algorithm for said monitored characteristic.
In accordance with a second aspect, the present invention provides a computer readable medium having a computer program for carrying out the method of the first aspect of the present invention.
In accordance with a third aspect the present invention provides network management apparatus for processing data representing monitored characteristics in a network comprising network devices and links to provide a stress value representing the performance of the network, the apparatus comprising:
a network connection or port for receiving a raw value of data for a monitored characteristic of a network device or link;
a processor for comparing said raw value with a predetermined threshold value for said monitored characteristic obtained from memory; and if the comparison determines that raw data value is greater than or equal to said threshold value, providing a stress value equal to a default value, said default value being a maximum or minimum value of a predefined bounded range; and if the comparison determines that said raw value is less than said threshold value, calculating a stress value within said predefined bounded range using an appropriate algorithm for said monitored characteristic stored in memory.
The present invention thus obtains a value for the stress of a network, network object or part thereof, within a predefined, bounded range, that is to say a xe2x80x9cnormalisedxe2x80x9d stress value. Since the stress value is a normalised value, is easy to understand, and requires no interpretation by the network manager.